** How to setup CPU/MCH GTL Ref Voltages Vs. EasyTune **

[Lsdmeasap]

This is a work in progress, and I will be adding to it with images and examples. This is part of my P45 Review/Guide I am working on.

Just thought I would toss this out there and add a link to it in my signature as I have posted this at a few forums and just felt bad not having this info readily available to my favorite forum.

Keep in mind this is in the works, but all info is correct and relevant to all GA-P45 boards. So more will be added and then this will be a section in my review once I get it finished up. Just thought this may help some of you who venture into this area of your BIOS

Originally Posted by A Random User

For me, All the references in ET6 are wrong or always show the same defaults. Why is this?

That is ONLY because ET Shows the .xx % of Vtt of what you set in the BIOS. The Default Value of MCH Ref is .63% of Vtt at stock of 1.20V, which is .756 (.76) . The reflected value in the BIOS and Easytune MCH Ref % is also always x Stock Vtt, so don't let what you see as you change Vtt back to what you want to use throw you off.

Why is this important? I feel that the default of .76 is to much, especially for a overclocked system when trying to gain stability. I believe between .68-.72 is often best. Of course more or less may be needed depending on your board, your ram, your overall speeds, and other voltage settings.

The Ref Settings in the BIOS are .xx % values of/X Stock Vtt so this tends to throw off many users when they set something and then compare to EasyTune. So you need to keep the % amounts in mind when changing these Ref voltages, and it is easiest to do it at stock Vtt (unless you need a % Value Stock Vtt will not allow you to choose, if so adjust accordingly) and then raise your Vtt back up to where you want to run it. If you Make any deviation from the stock % for MCH Ref of .63% the value will be reflected in ET

EasyTune ________ Actual % Of Stock Vtt
.76 _____________________ .63
.75 _____________________
.745 ____________________ .621
.73 _____________________ .61
.72 _____________________
.715 ____________________ .5977
.70 _____________________ .585
.69 _____________________
.685 ____________________ .575

Here is Five Common examples of this, all using MCH Ref, and various Vtt (Termination) voltages with images showing how each % is possible. All of these but the last WILL Change what you see for MCH Ref in EasyTune as well. This way I hope you can see how this works, and then maybe better find your way to tuning your Ref voltages

*** Examples below are percentages ranging between 57.5% - 63% (.685V - .76V) with Vtt always at 1.28V ***

Those ranges .685-.76 are actual values of 57.5%-63% of stock Vtt, varying off from the .76 (63%) stock setting. Some Percentage values will be rounded off for simplicity.


(MCH Ref .685% AKA .685 in ET **57.5% Actual**)



This example shows if you set 1.20 Vtt and then set your MCH Ref to .685 and then raise Vtt back to 1.28, ET would show .685 MCH Ref as .7350V would be .685% of Vtt (1.28 x .5745 = .735) ~ Stock Vtt 1.20 x .5745 = 6894% of stock Vtt (Thus .685%)


(MCH Ref .70% AKA .70 in ET **58.5% Actual**)



This example shows if you set 1.20 Vtt and then set your MCH Ref to .70 and then raise Vtt back to 1.28, ET would show .70 MCH Ref as .75008V would be .70% of Vtt (1.28 x .586 = .75008) ~ Stock Vtt 1.20 x .586 = .7032% (Thus .70%)

(MCH Ref .715% AKA .715 in ET **59.5%-60% Actual**)



This example shows if you set 1.20 Vtt and then set your MCH Ref to .715 and then raise Vtt back to 1.28, ET would show .715 MCH Ref as .765V would be .715% of Vtt (1.28 x .5977 = .7650) ~ Stock Vtt 1.20 x .5997 = .7172% of stock Vtt (Thus .715%)

(MCH Ref .73% AKA .73 in ET **61% Actual**)



This example shows if you set 1.20 Vtt and then set your MCH Ref to .73 and then raise Vtt back to 1.28, ET would show .73 MCH Ref as .780V would be .73% of Vtt (1.28 x .61 = .7808) ~ Stock Vtt 1.20 x .61 = .732% of stock Vtt (Thus .73%)

(MCH Ref .745% AKA .745 in ET **62% Actual**)



This example shows if you set 1.20 Vtt and then set your MCH Ref to .xx and then raise Vtt back to 1.28, ET would show .745 MCH Ref as .7948V would be .745% of Vtt (1.28 x .621 = .79488) ~ Stock Vtt 1.20 x .621 = .745% of stock Vtt (Thus .745%)

*** STOCK MCH Ref values at .63% (.76V) To show how ET seems to often or always show .76 and confuse users ***

First Example shows stock values for Ref used, .63%. That would be MCH Ref manually set but Value unchanged (.76) and then Vtt Raised to 1.28.

(Stock MCH Ref W/ 1.28 Vtt / .76 in ET **63% Actual**)



This example shows if you set 1.20 Vtt and then manually set your MCH Ref to .756 and then raise Vtt to 1.28, ET would show .76 MCH Ref as .810V would be .76% of Vtt (1.28 x .633 = .81024) ~ Stock Vtt 1.20 x .63 = .756% of stock Vtt (Thus .63%)

This following example shows Stock Vtt and Stock MCH Ref used.........

(Stock MCH Ref W/1.20 Vtt or .76 in ET **63% Actual**)



This example shows if you set 1.20 Vtt and then manually set your MCH Ref to .756, ET would show .76 MCH Ref as .756V would be .76% of Vtt (1.20 x .63 = .756) ~ Stock Vtt 1.20 x .63 = .756% of stock Vtt (Thus .63%)


That is just ONE example, and how to manipulate it, of the Many Ref Voltages in the BIOS Vs. what you see in Easytune. Here are all the values affected by other Values in the BIOS and their respective default percentages.

CPU Termination (Vtt) Automatically changes the following if manually set >>>

CPU Reference Voltage (.63% of Default Vtt/1.20) .76 ET
CPU Reference2 Voltage (.67% of Default Vtt/1.20) .80 ET
MCH Reference Voltage (.63% of Default Vtt/1.20) .76 ET

DRAM Voltage Automatically changes the following if manually set >>>

MCH/DRAM Reference Voltage (.50% of Default Dram Voltage)
DRAM Termination Voltage (.50% of Default Dram Voltage)
Channel A Reference Voltage (.50% of Default Dram Voltage)
Channel B Reference Voltage (.50% of Default Dram Voltage)

If you want a higher or lower than stock % / Value for any of the above settings you will find it easier to set the Dram Voltage or Vtt back to stock (Or above or below to find and be able to choose alternate % Values), then adjust desired setting to the % / Value you wish to use.

Then once you have selected a % range you want to use for said setting then go back and raise your Vtt or Dram Voltage back to what you choose to use and the corresponding settings will self adjust and still be set to the .xx % amount that you set them to.

[Lsdmeasap]

Updated from my review for TrevorC

[MaxFX]

Can you please explain why it is so important to set all these values correct. I mean it's a myriad of things and it can drive a sane persson crazy LOL.

I have my system pretty overclocked but what can I gain for setting all these values at a special value. If it's all stable in every stresstesting prog out there should I then bother to mix around ?

In games it often flicker/flashing the textures and I cant let the damn thought go that it maybe some settings that not correct. do you think it's possible that it can be so and thats why I keep getting this artifacts ?

I mean if it's all stable in everything a throw at my comp e.x OCCT / Orthos / Memtest86+.

One should think that if everything is stable then I should not have any problem in games whatsoever or ?

It cant be that my NB overheating eatier as I said every stress progs works like a charm. so please chime in and let me hear your thougts on all of this!

[Dodgexander]

Yes, I would also like to know this. I notice this, along with the thread in Xtreemsystems, as you have mentioned LSDMeasap, setting this to Auto makes sure its value is correct, so what is the advantage of setting this manually? Are we missing out on something?

[Nickel020]

The reference voltages help for the last few percent to get the absoulte maximum overclock. If you can overclock to 4100MHz without adjusting them you can maybe overclock to 4150 or 4200MHz if you tweak them.
At lower overclocks they might enable to go down with VCore a tiny little bit (like 1-3 steps in BIOS), but tweaking them is not really worth it there imho.

[Lsdmeasap]

@ MaxFX
If you are stable in OCCT/Orthos/Prime/Memtest or Intel Burn test then you have no need to change this setting.

This is only need for stability or in trying super high clock speeds, otherwise you do not need to adjust if you are stable in Auto

Games flickering or flashing is likely your GFX Card is overheating or your PSU is not giving it enough power possibly

@ Dodgexander

The Auto setting on this is not always "Correct" it is only a constant Value of 63% (.76) of your set Vtt voltage. So what is "Correct" all depends on what you are running, and what Vtt you are using.

For example if you are using to much or to little Vtt and want to keep it that way (For some reason) then you may need to adjust this so you get the correct amount. Or if you are using the incorrect Vtt and do not know it, adjusting this can get you stable as well.

And as said above, this will also when set properly allow you to clock higher then normally possible and can allow you to also lower voltages across the board (Vcore/Vtt/MCH)

[MaxFX]

Okey thanks for the answer guys, so I see it's pretty much just for getting it more stable, to squeese the few extra mhz as you say. that sounds pretty much what I was thinking to :)

About the gfx cards, yepp the first thing I was thinking about was the gfx card but nope it do not overheat/ or are to much overclocked so thats not the problem.

I think it must be the new games as Vorlon and I was talking about in another thread.

So I guess one have to live with it, it may be a thing called C-Fighting
Z-fighting - Wikipedia, the free encyclopedia

And these artifacts always shows up in the same spot in the games so it's pretty obvious that it's the way the game is rendered and not my hardware who fails!

Just dident think so much about this before but since upgraded my comp with all new stuff then i suddenly looking for every damn fault I can find LOL

BTW I upped to the great Corsair 1000W PSU when I bought my GTX 285 as the old PSU couldent handle my 8800GT for PhysX and GTX 285 together!

[thepieguy]

There are a couple of things I can't figure out here. If you are changing your Reference voltages, should you be changing CPU, MCH, or both? Or "it depends on your setup"? If changing both, should they be the same?

[Lsdmeasap]

Originally Posted by MaxFX

Okey thanks for the answer guys, so I see it's pretty much just for getting it more stable, to squeese the few extra mhz as you say. that sounds pretty much what I was thinking to :)

About the gfx cards, yepp the first thing I was thinking about was the gfx card but nope it do not overheat/ or are to much overclocked so thats not the problem.

I think it must be the new games as Vorlon and I was talking about in another thread.

So I guess one have to live with it, it may be a thing called C-Fighting
Z-fighting - Wikipedia, the free encyclopedia

And these artifacts always shows up in the same spot in the games so it's pretty obvious that it's the way the game is rendered and not my hardware who fails!

Just dident think so much about this before but since upgraded my comp with all new stuff then i suddenly looking for every damn fault I can find LOL

BTW I upped to the great Corsair 1000W PSU when I bought my GTX 285 as the old PSU couldent handle my 8800GT for PhysX and GTX 285 together!

Hey, I don't know? That could be the cause maybe? Or it could just be that/those few games particular drivers as well. Does it happen in all games or just certain ones?

Originally Posted by thepieguy

There are a couple of things I can't figure out here. If you are changing your Reference voltages, should you be changing CPU, MCH, or both? Or "it depends on your setup"? If changing both, should they be the same?

No, you can set them both if you like, or just one or the other. I did not write any info about CPU Ref voltage adjustments because it is a much harder thing to get tweaked the correct way.

Here is some in depth reading on how to setup CPU Ref voltages >>
Understanding GTL Reference Voltage

And here is some more reading on setting up Ref voltages in General >>
How to set up GTL Ref Values for 45nm & 65nm - XtremeSystems Forums

[MaxFX]

Hello!
Well it's mostly in all games I have tested but in some theres less so it must be the driver/games and nothing to worry about. havent seen any texture coruption in BioShock in the few minutes I have played :)

As I said it's allways in the same place no matter if I run my comp at default and gfx card. I was just wondering if it could have been som prob with the
Ref voltages as I dident really know whats that was for and the same goes for pretty much ever damn setting as theirs a myriad e.x PCI clock drive/ CPU clock drive - CPU clock skew/ MCH clock skew bla bla the list goes on and it only gives me a headache trying to understand and REMEMBER what every settings does

But when you said I dont really need to adjust them as it's all stable in every test progs I throw at it I feel more relaxed and calm as it was just like I had hoped, you only need to tinker with all this should I say crap when you are pushing it to the limits so you can get some few more mhz.

I understand the CPU PLL and VTT a little as we have spoken about them before and I have read up on them. so thats a good thing to keep an eye on I think and thats prolly the most important settings for keeping it stable!

BTW nice to have som links to the Ref voltages and what they do so I can read up and learn a little if i got the urge for it :)